IMAGE FEATURE EXTRACTION APPARATUS, IMAGE RETRIEVAL SYSTEM, VIDEO FEATURE EXTRACTION APPARATUS, AND QUERY IMAGE RETRIEVAL SYSTEM, AND THEIR METHODS, PROGRAM, AND COMPUTER READABLE RECORDING MEDIUM

PROBLEM TO BE SOLVED: To provide an image feature extraction apparatus having versatile applicability and a wide application range. SOLUTION: The image feature extraction apparatus 1 is provided with a DCT transformer 3 for generating a DCT quantization result obtained by executing DCT transform of YUV values converted from RGB values of image data and quantizing the DCT transform result, an element selection part 2 for selecting a DCT element from DCT elements of the DCT quantization result on the basis of an element selection table for selecting a DCT element corresponding to a feature to be extracted and outputting a feature bit string obtained by allocating a code to the selected DCT element, and a real number index conversion part 4 for converting the feature bit string output from the element selection part 2 into a real number index. COPYRIGHT: (C)2008,JPO&INPIT